diff --git a/public/js/app.js b/public/js/app.js
index bdd9baa..e3fd69b 100644
--- a/public/js/app.js
+++ b/public/js/app.js
@@ -6,6 +6,7 @@ const state = {
     markers: {},
     trails: {}, // Track position trail polylines for each node
     nodeLastHeard: {}, // Track last heard times for flash detection
+    nodeLastColor: {}, // Track last assigned color to prevent flipping
     refreshIntervals: [],
     timeUpdateInterval: null,
     lastSuccessfulUpdate: Date.now(),
@@ -296,7 +297,7 @@ const ui = {
         return 0.2;
     },
 
-    getMarkerColor(lastHeardDate) {
+    getMarkerColor(lastHeardDate, nodeId) {
         if (!lastHeardDate) return '#a50026'; // Darkest red for unknown
 
         // Handle SQLite datetime format
@@ -324,8 +325,32 @@ const ui = {
         // 8 buckets over 360 minutes = 45 minutes per bucket
         const bucketSize = 360 / 8;
         const bucketIndex = Math.min(7, Math.floor(minutesSince / bucketSize));
+        const newColor = colors[bucketIndex];
 
-        return colors[bucketIndex];
+        // Apply hysteresis: only change color if we're at least 2 minutes into the new bucket
+        // This prevents flipping at boundaries
+        if (nodeId && state.nodeLastColor[nodeId]) {
+            const lastColor = state.nodeLastColor[nodeId];
+            const lastIndex = colors.indexOf(lastColor);
+
+            // If we're in a different bucket, check if we're far enough in
+            if (lastIndex !== -1 && lastIndex !== bucketIndex) {
+                const minutesIntoBucket = minutesSince % bucketSize;
+                const minutesFromBoundary = Math.min(minutesIntoBucket, bucketSize - minutesIntoBucket);
+
+                // Need to be at least 2 minutes away from boundary to change color
+                if (minutesFromBoundary < 2) {
+                    return lastColor; // Keep the old color
+                }
+            }
+        }
+
+        // Store the color for this node
+        if (nodeId) {
+            state.nodeLastColor[nodeId] = newColor;
+        }
+
+        return newColor;
     },
 
     getChannelName(channelNumber) {
@@ -877,14 +902,25 @@ function displayPositions(positions) {
     positions.forEach(pos => {
         seenNodes.add(pos.node_id);
         const opacity = ui.getMarkerOpacity(pos.last_heard || pos.timestamp);
-        const color = ui.getMarkerColor(pos.last_heard || pos.timestamp);
+        const color = ui.getMarkerColor(pos.last_heard || pos.timestamp, pos.node_id);
 
-        // Check if node is newly heard (last_heard changed recently)
-        const currentLastHeard = pos.last_heard || pos.timestamp;
+        // Normalize timestamps for comparison
+        const normalizeTimestamp = (ts) => {
+            if (!ts) return null;
+            let dateStr = ts;
+            if (ts.includes(' ') && !ts.includes('T')) {
+                dateStr = ts.replace(' ', 'T') + 'Z';
+            }
+            return new Date(dateStr).getTime();
+        };
+
+        // Check if node is newly heard (last_heard changed in the last 10 seconds)
+        const currentLastHeard = normalizeTimestamp(pos.last_heard || pos.timestamp);
         const previousLastHeard = state.nodeLastHeard[pos.node_id];
-        const isNewlyHeard = previousLastHeard && currentLastHeard !== previousLastHeard;
+        const timeSinceUpdate = currentLastHeard - (previousLastHeard || 0);
+        const isNewlyHeard = previousLastHeard && timeSinceUpdate > 0 && timeSinceUpdate < 10000;
 
-        // Update tracked last heard time
+        // Update tracked last heard time (store normalized timestamp)
         state.nodeLastHeard[pos.node_id] = currentLastHeard;
 
         // Add pulsing animation for newly heard nodes
@@ -897,6 +933,9 @@ function displayPositions(positions) {
             iconAnchor: [8, 8]
         });
 
+        // Use last_heard for consistency (fallback to timestamp if not available)
+        const relevantTimestamp = pos.last_heard || pos.timestamp;
+
         const popupContent = `
             <div style="position: relative; min-width: 180px; padding-bottom: 8px;">
                 <b>${escapeHtml(pos.long_name || pos.short_name || pos.node_id)}</b><br>
@@ -904,7 +943,7 @@ function displayPositions(positions) {
                 Lat: ${pos.latitude.toFixed(6)}<br>
                 Lon: ${pos.longitude.toFixed(6)}<br>
                 ${pos.altitude ? `Alt: ${pos.altitude}m<br>` : ''}
-                <span class="relative-time" data-timestamp="${pos.timestamp}">${ui.formatRelativeTime(pos.timestamp)}</span>
+                <span class="relative-time" data-timestamp="${relevantTimestamp}">${ui.formatRelativeTime(relevantTimestamp)}</span>
                 <div style="margin-top: 8px; display: flex; gap: 8px; align-items: center;">
                     <a href="#"
                        onclick="event.preventDefault(); window.showNodeDetail('${pos.node_id}'); return false;"
@@ -1126,18 +1165,23 @@ function updateMapMarkerOpacity() {
         if (!timestampMatch) return;
 
         const timestamp = timestampMatch[1];
-        const opacity = ui.getMarkerOpacity(timestamp);
-        const color = ui.getMarkerColor(timestamp);
+        const newOpacity = ui.getMarkerOpacity(timestamp);
+        const newColor = ui.getMarkerColor(timestamp, nodeId);
 
-        // Update marker icon with new opacity and color (only if it changed significantly)
+        // Get current icon properties
         const currentIcon = marker.getIcon();
         const currentOpacity = currentIcon?.options?.html?.match(/opacity: ([\d.]+)/)?.[1];
-        const currentColor = currentIcon?.options?.html?.match(/background-color: ([^;]+);/)?.[1];
+        const currentColor = currentIcon?.options?.html?.match(/background-color: ([#\w]+)/)?.[1];
 
-        if (!currentOpacity || Math.abs(parseFloat(currentOpacity) - opacity) > 0.05 || currentColor !== color) {
+        // Only update icon if opacity changed significantly (>0.1) OR color bucket changed
+        const opacityChanged = !currentOpacity || Math.abs(parseFloat(currentOpacity) - newOpacity) > 0.1;
+        const colorChanged = currentColor !== newColor;
+
+        // Only update if there's a meaningful change (avoid flashing on minor updates)
+        if (opacityChanged || colorChanged) {
             const icon = L.divIcon({
                 className: 'custom-marker',
-                html: `<div style="opacity: ${opacity}; background-color: ${color}; width: 12px; height: 12px; border-radius: 50%; border: 2px solid white; box-shadow: 0 2px 4px rgba(0,0,0,0.3);"></div>`,
+                html: `<div style="opacity: ${newOpacity}; background-color: ${newColor}; width: 12px; height: 12px; border-radius: 50%; border: 2px solid white; box-shadow: 0 2px 4px rgba(0,0,0,0.3);"></div>`,
                 iconSize: [16, 16],
                 iconAnchor: [8, 8]
             });